feat(nvim): v0.11: Use native LSP, Completion, Diagnostics

- Move all language LSP configurations to `nvim/lsp`
- Move nvim LSP configurations to `nvim/lua/core`
- Remove LSP attach keymaps where default ones exists and are usable
- Reorged LSP attach keymaps per plugin
- Move Lazy.nvim configurations to `nvim/lua/core`
- `nvim/init.lua` cleaned to only load other files
- Uniform diagnostics symbols across lualine & gutter

common/.config/nvim/lsp/jsonls.lua

@@ -0,0 +1,15 @@
+return {
+    -- lazy-load schemastore when needed
+    on_new_config = function(new_config)
+        new_config.settings.json.schemas = new_config.settings.json.schemas or {}
+        vim.list_extend(new_config.settings.json.schemas, require("schemastore").json.schemas())
+    end,
+    settings = {
+        json = {
+            format = {
+                enable = true,
+            },
+            validate = { enable = true },
+        },
+    },
+}